Arrangement for generating tilting oscillations



June 8, 1937. K. SCHLESINGER ARRANGEMENT FOR GENERATING TILTINGOSCILLATIONS Filed May 2,- 1933 Patented June 8, 1937 'UNlTED STATESARRANGEMENT FOR GENERATING TILTING OSCILLATIONS Kurt Schlesinger,Berlin, Germany Application May 2, 1933, Serial No. 668,940

Germany May 2, 1932 11 Claims.

Discharge tubes are already known having a hot cathode, a grid and a gasfilling of relatively high pressure (for example V atmosphere). thesedischarge tubes the grid does not act as a 5 control element but asblocking element. As

long as the control grid possesses a corresponding negative potential adischarge does not take place, however high the potential may be betweenthe anode and thecathode. Immediately,

10 however, the discharge-by shifting of thegrid potential-hasoncecommenced, the same-irrespective of any variation in the gridpotentialcontlnues as long as a potential exists between the cathode andthe anode.

The subject matter of the invention is an improved arrangement makinguse of these discharge tubes of the kind known per se, for generatingself-controlled (so-called free relaxation oscillations) orforeign-controlled (induced) reso laxation oscillations. v

The invention comprises means to decrease, in a connection system of thementioned type, the

' rate of discharge to such extent as to allow the occurrences concernedaccurately to be govu erned.

The invention also comprises improved charging means.

Furthermore, the invention comprises means to prevent currents fromflowing in the grid cir- 30 cults of the above mentioned discharge tube,as to increase ,the steadiness of the occurrences concerned.

For the generation of foreign-controlled relaxation oscillations thepotential of the charg- 35 lng condenser, which is charged inchronologically linear fashion, possibly with the assistance of a screengrid tube, in the manner known per se, is, in accordance with theinvention, applied between the cathode and the anode, and the controlpotential to the correspondingly negativeblassed grid. For producingself-controlled relaxation oscillations the control potential inaccordance with the invention is derived from the relaxation oscillationpotential, for example by 45 means of a potential divider connectionsystem.

Capacitative dividing of the potential is particularly suitable for thepurpose of the invention, as leakage currents do not take place inconnection therewith. Naturally. however, it is also 50 possible toemploy highly ohmic division of the potential, and if necessary also aninductive division of the potential.

Preferably, foreign control and self-control may be comblnedwith eachother-in the arrange-- tion of this character possesses the advantagethat the relaxation oscillation does not cease upon momentary failure onthe part of the foreign control potential. This arrangement possessesparticular advantages in connection with 5 television receivingarrangements.

The arrangement according to the invention permits of the use ofignition potentials as desired, as the ignition potential in the case ofa given frequency depends solely on the extent of the charging current.The quenching potential is equal to zero". The charging condenser iscompletely discharged. The arrangement permits of very exact control atthe merely weakly negative-biased grid. A further appreciable advantageof the arrangement resides in the fact that the same also enablesrelatively small ignition potentials-approximately 150-200 voltsto beemployed. I

Other objects and embodiments of the invention will be more fullyunderstood from the appended drawing, whereof Fig. 1 shows anarrangement for generating foreign-controlled relaxation oscillations,whilst in Fig. 2 there is shown an embodiment of the present invention.

Fig. 3 shows a. special feature of the invention.

In the drawing i is the, discharge tube, which is filled with gas ofapproximately mm.-1 mm. atmosphere, (thegas pressure depends on thepeculiar gas the tube is to be filled with) having the hot cathode 4,the grid 3 and the anode 2. 8 is the grid bias battery. The controlpotential is represented in symbollcal fashion by 9. 5 is the chargingcondenser. At 6 and 'I there is fed the charging current, which servesfor chronologicallinear charging of the charging condenser 5, and maybeproduced by means of a screen d tube. v 4

Thearrangement operates in the following manner: At first the condenser5 is charged to the ignition potential, which may be selected asdesired, and in the case of a given frequency depends only on the extentof the charging current. A discharge cannot take place so long as thegrid 3 receives the requisite negative bias (for example, approximately1, 10 or -20 volts) through the medium of the battery 8. At the momentwhen the negatlve-biassed grid has been raised by the control potentialto a sufficiently high potential the discharge commences. The dischargecontinues until the condenser 5 has been completely discharged. Thequenching potential is accordingly equal to zero. The re- According tothe invention, the anode is furnished with a constant positivepotential, whilst the grid is furnished with alikewise constant negativebias. The potential of the cathode is shifted during the chargingoperation into negative until the potential of the-negative-biassed gridhas become to such extent positive in relation .to the cathode that thetube is able to ignite.

(The difference in potential between grid and cathode necessary forignition is dependent on the nature of the filling gas.)

For charging purposes there is employed a screen-grid charging tubehaving a reciprocal of the amplification factor of less than Aoo%, thegrid situated next to the anode *serving forcontrol, whilst the gridsituated in the vicinity of the cathode is preferably raised to cathodepotential.

The frequency of the relaxation oscillation may be regulated byvariation of the charging current and/or by variation of the chargingcondenser, .According to the invention, the control potential of thescreen grid charging tube is taken at a potentiometer, and at the sametime there are provided a number of charging condensers, which arecapable of being connected as desired and which determine the frequencyrange.

The relaxation oscillation potential to be conducted to the consumer isalso taken via a potentiometer. By varying the adjustment of thepotentiometer the amplitude of the relaxation oscillations may bechanged within wide limits. Further, there is provided in the receivingcircuit a counter-potential battery (which may also be replaced by apotentiometer), by the variation of which the position of the image inthe Braun tube may be adjusted in simple fashion.

The synchronization potential necessary for the generation of controlledrelaxation oscillations may, in accordance with the invention, beapplied to the grid of the hot glow tube through the medium of a highresistance. It has been found that the synchronization potential, in thesame manner as the negative bias, requires to be fed in such fashionthat a load on the grid is avoided to all possible extent, so that thegrid during the ignition process is able to assume instantaneously thepotential corresponding with the run of the field.

Furthermore it was ascertained that the tilting potentials (moreparticularly the extremely rapid return) cause considerable electricaldisturbances in thevicinity of the tilting oscillation generator.According, therefore, to the inv ntion, all lines leading flutteringpotentials, and also the hot glow tube itself, are completely screenedofi. The tube is arranged together with the said lines in a specialscreening casing, and the lines within the casing are again furnishedwith special screening means.

In Fig. 2 there is shown a form of embodiment of the arrangementaccording to the invention, by Way of example. In the same I is the hotglow tube with the grid 2, to which there is conducted over theresistance 2| the negative bias,

and over the resistance 20 and the condenser 4| the synchronizingpotential from the terminals 3|, 32. 3 is the cathode of the hot glowtube. According to the invention a low ohmic resistance 28 is arrangedin the discharge circuit of the tube l, which serves for delaying therate of the return. This resistance may have, for example, a value ofabout 1 ohm. In the anode circuit of the screen grid charging tube withthe anode 26 and the screen grid 38 acting as control grid there aresituated the charging condensers l1. l8 and I9 capable of beingconnected as desired, which condensers may be selected at, say, .5 mf.,.05 mi. and 5000 cm. Naturally, it is possible to provide a largernumber of condensers. or to select condensers of other sizes. Theadjustment of the frequency of the relaxation oscillation is performedby regulation of the bias of the grid 38 of the screening grid tube bymeans of the potentiometer 25 and by selection of the correspondingtilting condenser. The operating potential, which is conducted by meansof the coupling resistances l5 and Hi to the terminals 29 and 30 of theconsuming apparatus, for example a Braun tube, is taken at thepotentiometer 2 3. By varying the potentiometer adjustment the amplitudeof the relaxation oscillations is changed within the practically desiredlimits. The counter-potential battery, as shown in the drawing, mayconveniently be replaced by the potentiometer 23. By adjustment of thispotentiometer there is determined the position of the image in the Brauntube. The hot glow lamp i, the condensers l1, I8 and I9, and also allleads are arranged within a screening casing 33. The leads maypreferably again be screened off within the casing which screening isshown in Fig. 2 by the chain-dotted line. Furthermore, additionaldisturbance-ridding measures, such as a wave filter 20, 50, chokes 5 and6 and condensers l and 8, etc., may also be provided. The heatingelements 4 and I0 of the indirectly heated cathodes 3 and 9 may beheated for example in direct fashion by the mains in parallelconnection. The remaining working current is if necessary also supplied,from the mains through the medium of the steadying device 21. It hasbeen found convenient to select the resistance 20 at approximately 10ohms, the resistance 2| at approximately 3-10 ohms, the

resistance 15 and 16 at approximately 5000 and 10000 ohms, and thepotentiometers 23, 24 and 25 at approximately 10 ohms, 0.5-10 ohms and25000 ohms. The condenser M may conveniently be selected at 10 cm., thecondensers l and 8- each at 5000 cm.

Naturally the invention is in no way limited to the form of embodimentas described. Thus, for example, it is quite readily possible to providethe total arrangement in a screening casing, and to employ also otherknown disturbance-ridding means beyond those stated by way of example.

There may be essential as regards this embodiment of the invention thatthe c ontrolupon the generation of free tilting oscillationstakes placeinto negative by shifting ofi the cathode potential, that the negativebias and also the synchronizing potential are conducted to the grid overhigh ohmic resistances for the purpose of producing induced relaxationpotentials, that a plurality of tilting condensers are provided, whichare capable of being selected or varied as desired, and bymeans of whichthere is determined the frequency range of the tilting oscillater-potential, which permits of adjustment of the 4 position of theimage, and that the hot-cathode glow' tube itself together with alllines leading fluttering potential is screened oif in such fashion thatelectrical disturbances are avoided in the vicinity of the tiltingcondenser.

Though each kind of gas-filled, hot-cathode, three-electrode tubes maybe employed for the arrangements according to the invention, preferablytubes may be employed, which are constructed in such fashion that thecold glow discharge only takes place at potentials which are as high aspossible. 4

In Fig. 3, l-9 designate the same parts as in Fig. 1. Ill is a limitingresistance, which prevents the occurrence of a grid current upon thedischarge, l2 the second condenser of the capacitative potentialdivider, which is made considerably, for example 100 times, larger thanthe main condenser 5, and in accordance with the invention mayconveniently be constructed in the form of a rotary plate condenser. IIis a counter-potential battery of preferably very few volts, which hasthe object of eliminating any remaining potential, and accordinglyensures proper quenching.

In the case of pure self-control the grid 3, which is biassed negativelyby the battery 8, is charged by the charging current in the same manneras the main condenser, but considerably more slowly than the maincondenser in accordance with the ratio given by the potential divider.The relaxation frequency, therefore, may be adjusted as desired bysuitable adjustment of the potential. divider. When combiningforeign-control and self-control, the foreign-control potential may besupplied at 9.

' The use of the connection systems according to the invention enablescompletely even synchronization to be obtained and to reduce the returnperiod to such extent that the return line is almost entirely invisible.

I claim:

1. An arrangement for producing relaxation oscillations comprising agaseous discharge device including a cathode, a control electrodeand ananode, means for producing the charging current, said charging meansbeing connected with said anode on the one hand and with said cathode onthe other hand; an auxiliary condenser being connected to said cathodeon the one hand and to said control electrode on the other hand; a maincharging condenser being connected to said control electrode on the onehand and to the anode on the other hand, said main charging condenserbeing smaller than said auxiliary condenser for producing avoltage-division; means for supplying said control electrode with anegative bias; means to supply said control electrode with asynchronizing voltage and a resistance being arranged'in the leadconnection of said negative bias to said control electrode and aresistance arranged in the lead connection of said synchronizing controlvoltage to said control electrode.

2. An arrangement for producing relaxation oscillations comprising agaseous discharge device including a cathode, a control electrode and ananode, meansfor producing the charging ourrent, said charging meansbeingconnected with said anode on the one hand and with said cathode onthe other hand; an auxiliary condenser being connected to said cathodeon the one hand and to said control electrode on the other hand; a maincharging condenser being connected to said control electrode on the onehand and to said anode on the other hand, said main charging the leadconnection of said synchronizing control voltage to said controlelectrode.

. 3. An arrangement for producing relaxation oscillations for televisionpurposes comprising a gaseous discharge device including a hot cathode,a grid, and an anode; a condenser, a resistance of low value, means forcharging said condenser, means to connect said discharge device, saidcondenser, and said resistance to form a discharge circuit, and means toapply a bias to said grid.

4. An arrangement for producing relaxation oscillations for televisionpurposes comprising a gaseous discharge device including a hot cath-.ode, a grid, and an anode; a condenser, a resistance of low value,means 'for charging said condenser, means to connect said dischargedevice, said condenser, and said resistance to form a discharge circuit,means to apply a bias to said grid, and means to apply a synchronizingpotential to said grid.

5. An arrangement for producing relaxation oscillations for televisionpurposes comprising a gaseous discharge device including a hot cathode,a grid, and an anode; a condenser. a resistance of the order of 1 ohm,means for charging said condenser, means to connect said dischargedevice, said condenser, and said resistance to form a discharge circuit,means to apply a bias to said grid, and means to apply a synchronizingpotential to said grid.

6. An arrangement for producing relaxation oscillations for televisionpurposes comprising a gaseous discharge device including a hot cathode,a grid, and an anode; a condenser, a resistance of -low value, means forcharging said condenser, said means including a charging tube having anauxiliary grid of the screen grid type, means to connect said dischargedevice, said condenser and said resistance to form a discharge circuit,means to apply a bias to said grid, and

means to apply a synchronizing potential to the grid of said dischargedevice.

'7. An arrangement for producing relaxation oscillations for televisionpurposes comprising a gaseous discharge device including a hot cathagrid, and an anode, means for producing thev charging current, saidcharging means being connected with said anode on the one hand and withsaid cathode on the other hand; a main charging condenser, an auxiliarycondenser, and a resistance of low value being connected in series, saidseries connection being connected across the discharge space betweensaid anode and said cathode, said auxiliary condenser being connectedbetween said cathode and said grid, said main charging condenser beingsmaller than said auxiliary condenser for producing a voltage-division,means for supplying said grid with a negative bias, means to supply saidgrid with a synchronizing voltage and a high value resistance beingarranged in the lead connection of said negative bias to said grid and ahigh value resistance arranged in the lead connection of saidsynchronizing voltage to said grid.

9. An arrangement for producing relaxation oscillations for televisionpurposes comprising a gaseous discharge device, including a hot cathode,a grid, and an anode, means for producing the charging current, saidcharging means being connected with said anode on the one hand and withsaid cathode on the other hand; a main charging condenser, an auxiliarycondenser, a resistance of low value, and an auxiliary voltage sourcebeing connected in series, said series connection being connected acrossthe discharge space between said anode and said cathode, said auxiliaryvoltage source being arranged in the anode line to supply said anodewith a weak negative bias, said auxiliary condenser being connectedbetween said cathode and said grid, said main charging condenser beingsmaller than said auxiliary condenser for producing a vo1tage-division,means for supplying said grid with a negative bias, means to supply saidgrid with a synchronizing voltage, a high value resistance beingarranged in the lead connection of said negative bias to said grid, anda high value resistance arranged in the lead connection of saidsynchronizing voltage to said grid.

10. An arrangement for producing relaxation oscillations for televisionpurposes comprising a gaseous discharge device including a hot cathode,a grid, and an anode; a condenser, a resistance of low value, means forcharging said condenser, means to connect said discharge device, saidcondenser, and said resistance to form a discharge circuit, means toapply a bias to said grid,

and an encasing to screen ofi said discharge device, said chargingcondenser and all leads conducting the relaxation oscillation potential.

11. An arrangement for producing relaxation oscillations for televisionpurposes comprising a gaseous discharge device including a hot cathode,a grid, and an anode; a condenser, a resistance of the order of 1 ohm,means for charging said condenser, means to connect said dischargedevice, said condenser, and said resistance to form a discharge circuit,and means to apply'a bias to said grid, and an encasing to screen offsaid discharge device, said charging condenser and all leads conductingthe relaxation oscillation potential.

KURT SCHLESINGER.

